1. Field of the Invention
This invention relates to protoberberine derivatives represented by the following formula (I): ##SPC2##
wherein R.sub.1 is a lower alkoxy group; i.e. C.sub.1 to C.sub.5 alkoxy; R.sub.2 is a lower alkyl group, i.e. C.sub.1 to C.sub.5 alkyl, pyridyl group, phenyl group substituted by two or three lower alkoxy groups, i.e. C.sub.1 to C.sub.5 alkoxy or a phenyl-vinyl group substituted by two or three lower alkoxy groups, i.e. C.sub.1 to C.sub.5 alkoxy and to a process for producing the novel protoberberine derivatives of the above formula (I).
2. Description of the Prior Art
It has been known that some of the protoberberine derivatives, such as 5, 6, 13, 13a-tetrahydro-2, 3, 10, 11-tetramethoxy-8H-dibenzo [a, g] quinolizine have analgesic, vasodilating and hypotensive effects.
However, the known protoberberine derivatives to not exhibit in many cases sufficiently high analgesic, vasodilating and hypotensive effects and in addition, they exert a depressive effect on the central nervous system.